Conventionally, an apparatus for sorting cells has been widely utilized in the name of a flow cytometer for sorting cells suspending in a cell-suspending fluid. The apparatus for sorting the cells is provided with a cell alignment portion, which applies a process to the cell-suspending fluid, in which a great number of cells are suspended, and arrays the cells one by one in a row with a certain spacing therebetween, a cell information detecting portion, which applies a detecting process to the cells arrayed in a row by the cell alignment portion and detects information on the cells, and a cell sorting portion, which sorts the cells based upon the information detected by the cell information detecting portion.
As seen in FIG. 6, a cell alignment portion 100 of the above-described type of apparatus for sorting the cells has been conventionally known in the name of a sheath flow type. The cell alignment portion 100 is provided with a first nozzle 101, which possesses a cylindrical structure for letting a cell-suspending fluid 200 flow downward (in a downward direction in FIG. 6), and a second nozzle 102, which also possesses a cylindrical structure and is coaxially arranged surrounding the first nozzle 101. A sheath fluid 300 flows downward in the second nozzle 102 so as to surround the cell-suspending fluid 200 flowing downward in the first nozzle 101. The cell-suspending fluid 200 is hydrodynamically converged into a narrow flow by the sheath fluid 300, thereby the cells suspending in the cell-suspending fluid 200 is arrayed along the flow direction. In this case, a fluid passage diameter of the cell-suspending fluid 200 is narrowed corresponding to increase of a fluid pressure of the sheath fluid 300. The fluid passage diameter of the cell-suspending fluid 200 is enlarged corresponding to decrease of the fluid pressure thereof.
The above-described cell alignment portion 100 is illustrated in FIG. 11 of a Japanese Patent published as No. 2,749,906 (corresponding to a Japanese Patent Laid-Open published as No. 1991-122548). As described above, cells 400 suspending in the cell-suspending fluid 200 can be arrayed along the flow direction, thereby a cell information detecting portion (not shown) can apply an appropriate detecting process to each cell 400 and can properly detect information on each cell 400.
What is more, in the above-disclosed apparatus for sorting the cells, the flow of the cell-suspending fluid 200 is applied with supersonic vibration by an ultrasonic transducer and is converted into cell-containing liquid drops. However, the cells 400 contained in the cell-containing liquid drops, which are formed from the cell-suspending fluid 200 applied with the supersonic vibration, may be damaged. Therefore, the aforementioned method for forming the liquid drops by use of the supersonic vibration may not be recommended.
The present invention therefore seeks to provide an improved apparatus for sorting cells and a cell alignment substrate of the apparatus, by which the cells can be restrained from being damaged and a great number of cell-suspending liquid drops with a small diameter can be formed.